This invention relates to a method for manufacturing a structure which has fine ribs or projections arranged in a stripe, lattice or honeycomb pattern on its surface. The structure is used as a component part of a plasma display panel or of a chemical reaction apparatus. The invention also relates to a method for manufacturing a mold used for manufacturing the structure.
Attention is now being paid to a plasma display panel as an image display apparatus which is thin and has a big screen. The rear or front panel of the plasma display panel has fine ribs which constitute barrier walls and are arranged in a predetermined pattern. In the case of, for example, the rear panel, ribs with a width of about 50 .mu.m and a height of about 100 .mu.m are arranged at regular intervals in a stripe pattern.
Further, in a chemical apparatus, a structure with fine ribs (whose arrangement patterns depend upon their functions) is used as a filter for classifying fine particles; a catalyst; or a catalyst carrier for accelerating burning, synthesis, decomposition, etc.; a micro organism, or a polar plate.
These ribs are required to have a highly precise configuration and dimension. In the conventional art, such ribs are manufactured by various methods such as multiplex printing, pressure molding, etching, sand blast, an electrolytic treatment, an electric spark machining, etc.
As described above, structures with fine ribs are manufactured by various methods according to their respective configurations, purposes or properties required. These methods, however, have the following problems concerning precision in configuration or dimension, manufacturing cost, etc.:
a) In the case of multiplex printing, ribs are formed by repeating screen printing and curing ten or more times. Accordingly, the ribs have side surfaces of low flatness, and hence show a low precision in configuration and position. Further, the process of the manufacture of the ribs requires a great amount of time, which results in a high manufacturing cost. PA1 b) In the case of etching, if the rate of etching is increased to shorten the manufacturing time, the precision in configuration and position of each barrier wall inevitably decreases, with the result that the tips or bottom corners of the ribs cannot have desired configurations. In light of this, the etching rate cannot be increased, which means that a great amount of time and a high manufacturing cost are required. Moreover, the material of the ribs is limited to a chemically corrodable one. In addition, if the material of the ribs has a large crystal grain size, the ribs cannot have a high configuration precision, a high profile regularity, and cross sections which satisfy their specification. PA1 c) In the case of the sand blast, it is not easy to enhance the configuration precision since the cutting rate is greatly influenced by changes in working conditions. In particular, it is difficult to control the height of each rib with a high precision. Moreover, during working, a great amount of cutting particles or fine dust may occumulate, thereby contaminating the working environment or requiring additional labor for waste disposal. PA1 (a) To prepare a composite sheet which comprises an elastic surface layer and a base layer with a higher rigidity than the surface layer. The surface layer has grooves of a predetermined cross section arranged in a two-dimensional pattern. PA1 (b) To fill the grooves of the composite sheet with a paste material. PA1 (c) To cure the paste material to form ribs by evaporating solvent or chemical action. PA1 (d) To laminate a substrate on the composite sheet, and press the composite sheet against the substrate from the base layer side, thereby compressing the ribs and adhering them to the substrate. PA1 (e) To remove the ribs and the substrate from the composite sheet. As the result, the structure with fine ribs on the substrate is obtained. PA1 (a) A cylindrical electrode is prepared, which is supported such that it can rotate about an axis thereof, and has a plurality of grooves formed in an outer periphery thereof and extending circumferential. PA1 (b) The electrode is relatively moved in a first direction along a surface of an item to be treated, thereby subjecting the item to an electric spark machining and removing surface portions of the item which do not correspond to the grooves. PA1 (c) The electrode is further relatively moved along the surface of the item in a second direction crossing the first direction, thereby subjecting the item to another electric spark machining.